#include <CesiumGltfContent/GltfUtilities.h>

Classes
struct	IntersectResult
	Hit result data for intersectRayGltfModel. More...

struct	RayGltfHit
	Data describing a hit from a ray / gltf intersection test. More...

Static Public Member Functions
static std::optional< glm::dmat4x4 >	getNodeTransform (const CesiumGltf::Node &node)
	Gets the transformation matrix for a given node.

static void	setNodeTransform (CesiumGltf::Node &node, const glm::dmat4x4 &newTransform)
	Sets the transformation matrix for a given node.

static glm::dmat4x4	applyRtcCenter (const CesiumGltf::Model &gltf, const glm::dmat4x4 &rootTransform)
	Applies the glTF's RTC_CENTER, if any, to the given transform.

static glm::dmat4x4	applyGltfUpAxisTransform (const CesiumGltf::Model &model, const glm::dmat4x4 &rootTransform)
	Applies the glTF's `gltfUpAxis`, if any, to the given transform.

static CesiumGeospatial::BoundingRegion	computeBoundingRegion (const CesiumGltf::Model &gltf, const glm::dmat4 &transform, const CesiumGeospatial::Ellipsoid &ellipsoid=CesiumGeospatial::Ellipsoid::WGS84)
	Computes a bounding region from the vertex positions in a glTF model.

static std::vector< std::string_view >	parseGltfCopyright (const CesiumGltf::Model &gltf)
	Parse the copyright field of a glTF model and return the individual credits.

static std::vector< std::string_view >	parseGltfCopyright (const std::string_view &s)
	Parse a semicolon-separated string, such as the copyright field of a glTF model, and return the individual parts (credits).

static void	collapseToSingleBuffer (CesiumGltf::Model &gltf)
	Merges all of the glTF's buffers into a single buffer (the first one).

static void	moveBufferContent (CesiumGltf::Model &gltf, CesiumGltf::Buffer &destination, CesiumGltf::Buffer &source)
	Copies the content of one `CesiumGltf::Buffer` to the end of another, updates all `CesiumGltf::BufferView` instances to refer to the destination buffer, and clears the contents of the original buffer.

static void	removeUnusedTextures (CesiumGltf::Model &gltf, const std::vector< int32_t > &extraUsedTextureIndices={})
	Removes unused textures from the given glTF model.

static void	removeUnusedSamplers (CesiumGltf::Model &gltf, const std::vector< int32_t > &extraUsedSamplerIndices={})
	Removes unused samplers from the given glTF model.

static void	removeUnusedImages (CesiumGltf::Model &gltf, const std::vector< int32_t > &extraUsedImageIndices={})
	Removes unused images from the given glTF model.

static void	removeUnusedAccessors (CesiumGltf::Model &gltf, const std::vector< int32_t > &extraUsedAccessorIndices={})
	Removes unused accessors from the given glTF model.

static void	removeUnusedBufferViews (CesiumGltf::Model &gltf, const std::vector< int32_t > &extraUsedBufferViewIndices={})
	Removes unused buffer views from the given glTF model.

static void	removeUnusedBuffers (CesiumGltf::Model &gltf, const std::vector< int32_t > &extraUsedBufferIndices={})
	Removes unused buffers from the given glTF model.

static void	removeUnusedMeshes (CesiumGltf::Model &gltf, const std::vector< int32_t > &extraUsedMeshIndices={})
	Removes unused meshes from the given glTF model.

static void	removeUnusedMaterials (CesiumGltf::Model &gltf, const std::vector< int32_t > &extraUsedMaterialIndices={})
	Removes unused materials from the given glTF model.

static void	compactBuffers (CesiumGltf::Model &gltf)
	Shrink buffers by removing any sections that are not referenced by any BufferView.

static void	compactBuffer (CesiumGltf::Model &gltf, int32_t bufferIndex)
	Shrink a buffer by removing any sections that are not referenced by any BufferView.

static IntersectResult	intersectRayGltfModel (const CesiumGeometry::Ray &ray, const CesiumGltf::Model &gltf, bool cullBackFaces=true, const glm::dmat4x4 &gltfTransform=glm::dmat4(1.0))
	Intersects a ray with a glTF model and returns the first intersection point.

Detailed Description

A collection of utility functions that are used to process and transform a gltf model

Definition at line 30 of file GltfUtilities.h.

Member Function Documentation

◆ applyGltfUpAxisTransform()

static glm::dmat4x4 CesiumGltfContent::GltfUtilities::applyGltfUpAxisTransform	(	const CesiumGltf::Model &	model,
		const glm::dmat4x4 &	rootTransform )

static

Applies the glTF's gltfUpAxis, if any, to the given transform.

By default, the up-axis of a glTF model will the the Y-axis.

If the tileset that contained the model had the asset.gltfUpAxis string property, then the information about the up-axis has been stored in as a number property called gltfUpAxis in the extras of the given model.

Depending on whether this value is CesiumGeometry::Axis::X, Y, or Z, the given matrix will be multiplied with a matrix that converts the respective axis to be the Z-axis, as required by the 3D Tiles standard.

Parameters

model	The glTF model
rootTransform	The matrix that will be multiplied with the transform

Returns: The result of multiplying the rootTransform with the gltfUpAxis.

◆ applyRtcCenter()

static glm::dmat4x4 CesiumGltfContent::GltfUtilities::applyRtcCenter	(	const CesiumGltf::Model &	gltf,
		const glm::dmat4x4 &	rootTransform )

static

Applies the glTF's RTC_CENTER, if any, to the given transform.

If the glTF has a CESIUM_RTC extension, this function will multiply the given matrix with the (translation) matrix that is created from the RTC_CENTER in the. If the given model does not have this extension, then this function will return the rootTransform unchanged.

Parameters

gltf	The glTF model
rootTransform	The matrix that will be multiplied with the transform

Returns: The result of multiplying the RTC_CENTER with the rootTransform.

◆ collapseToSingleBuffer()

static void CesiumGltfContent::GltfUtilities::collapseToSingleBuffer ( CesiumGltf::Model & gltf )

static

Merges all of the glTF's buffers into a single buffer (the first one).

This is useful when writing the glTF as a GLB, which supports only a single embedded buffer.

Parameters

gltf	The glTF in which to merge buffers.

◆ compactBuffer()

static void CesiumGltfContent::GltfUtilities::compactBuffer	(	CesiumGltf::Model &	gltf,
		int32_t	bufferIndex )

static

Shrink a buffer by removing any sections that are not referenced by any BufferView.

Parameters

gltf	The glTF to modify.
bufferIndex	The index of the buffer to compact.

◆ compactBuffers()

static void CesiumGltfContent::GltfUtilities::compactBuffers ( CesiumGltf::Model & gltf )

static

Shrink buffers by removing any sections that are not referenced by any BufferView.

Parameters

gltf	The glTF to modify.

◆ computeBoundingRegion()

static CesiumGeospatial::BoundingRegion CesiumGltfContent::GltfUtilities::computeBoundingRegion	(	const CesiumGltf::Model &	gltf,
		const glm::dmat4 &	transform,
		const CesiumGeospatial::Ellipsoid &	ellipsoid = CesiumGeospatial::Ellipsoid::WGS84 )

static

Computes a bounding region from the vertex positions in a glTF model.

If the glTF model spans the anti-meridian, the west and east longitude values will be in the usual -PI to PI range, but east will have a smaller value than west.

If the glTF contains no geometry, the returned region's rectangle will be CesiumGeospatial::GlobeRectangle::EMPTY, its minimum height will be 1.0, and its maximum height will be -1.0 (the minimum will be greater than the maximum).

Parameters

gltf	The model.
transform	The transform from model coordinates to ECEF coordinates.
ellipsoid	The `CesiumGeospatial::Ellipsoid`.

Returns: The computed bounding region.

◆ getNodeTransform()

static std::optional< glm::dmat4x4 > CesiumGltfContent::GltfUtilities::getNodeTransform ( const CesiumGltf::Node & node )

static

Gets the transformation matrix for a given node.

This returns the node's local transform as-is. It does not incorporate transforms from any of the node's ancestors.

Parameters

node	The node from which to get the transformation matrix.

Returns: The transformation matrix, or std::nullopt if the node's transformation is invalid, .e.g, because it has a matrix with fewer than 16 elements in it.

◆ intersectRayGltfModel()

static IntersectResult CesiumGltfContent::GltfUtilities::intersectRayGltfModel	(	const CesiumGeometry::Ray &	ray,
		const CesiumGltf::Model &	gltf,
		bool	cullBackFaces = true,
		const glm::dmat4x4 &	gltfTransform = glm::dmat4(1.0) )

static

Intersects a ray with a glTF model and returns the first intersection point.

Supports all mesh primitive modes. Points and lines are assumed to have no area, and are ignored

Parameters

ray	A ray in world space.
gltf	The glTF model to intersect.
cullBackFaces	Ignore triangles that face away from ray. Front faces use CCW winding order.
gltfTransform	Optional matrix to apply to entire gltf model.

Returns: IntersectResult describing outcome

◆ moveBufferContent()

static void CesiumGltfContent::GltfUtilities::moveBufferContent	(	CesiumGltf::Model &	gltf,
		CesiumGltf::Buffer &	destination,
		CesiumGltf::Buffer &	source )

static

Copies the content of one CesiumGltf::Buffer to the end of another, updates all CesiumGltf::BufferView instances to refer to the destination buffer, and clears the contents of the original buffer.

The source buffer is not removed, but it has a byteLength of zero after this function completes.

Parameters

gltf	The glTF model to modify.
destination	The destination Buffer into which to move content.
source	The source Buffer from which to move content.

◆ parseGltfCopyright() [1/2]

static std::vector< std::string_view > CesiumGltfContent::GltfUtilities::parseGltfCopyright ( const CesiumGltf::Model & gltf )

static

Parse the copyright field of a glTF model and return the individual credits.

Credits are read from the glTF's asset.copyright field. This method assumes that individual credits are separated by semicolons.

Parameters

gltf	The model.

Returns: The credits from the glTF.

◆ parseGltfCopyright() [2/2]

static std::vector< std::string_view > CesiumGltfContent::GltfUtilities::parseGltfCopyright ( const std::string_view & s )

static

Parse a semicolon-separated string, such as the copyright field of a glTF model, and return the individual parts (credits).

Parameters

s	The string to parse.

Returns: The semicolon-delimited parts.

◆ removeUnusedAccessors()

static void CesiumGltfContent::GltfUtilities::removeUnusedAccessors	(	CesiumGltf::Model &	gltf,
		const std::vector< int32_t > &	extraUsedAccessorIndices = {} )

static

Removes unused accessors from the given glTF model.

Parameters

gltf	The glTF to remove unused accessors from.
extraUsedAccessorIndices	Indices of accessors that should be considered "used" even if they're not referenced by anything else in the glTF.

◆ removeUnusedBuffers()

static void CesiumGltfContent::GltfUtilities::removeUnusedBuffers	(	CesiumGltf::Model &	gltf,
		const std::vector< int32_t > &	extraUsedBufferIndices = {} )

static

Removes unused buffers from the given glTF model.

Parameters

gltf	The glTF to remove unused buffers from.
extraUsedBufferIndices	Indices of buffers that should be considered "used" even if they're not referenced by anything else in the glTF.

◆ removeUnusedBufferViews()

static void CesiumGltfContent::GltfUtilities::removeUnusedBufferViews	(	CesiumGltf::Model &	gltf,
		const std::vector< int32_t > &	extraUsedBufferViewIndices = {} )

static

Removes unused buffer views from the given glTF model.

Parameters

gltf	The glTF to remove unused buffer views from.
extraUsedBufferViewIndices	Indices of buffer views that should be considered "used" even if they're not referenced by anything else in the glTF.

◆ removeUnusedImages()

static void CesiumGltfContent::GltfUtilities::removeUnusedImages	(	CesiumGltf::Model &	gltf,
		const std::vector< int32_t > &	extraUsedImageIndices = {} )

static

Removes unused images from the given glTF model.

Parameters

gltf	The glTF to remove unused images from.
extraUsedImageIndices	Indices of images that should be considered "used" even if they're not referenced by anything else in the glTF.

◆ removeUnusedMaterials()

static void CesiumGltfContent::GltfUtilities::removeUnusedMaterials	(	CesiumGltf::Model &	gltf,
		const std::vector< int32_t > &	extraUsedMaterialIndices = {} )

static

Removes unused materials from the given glTF model.

Parameters

gltf	The glTF to remove unused materials from.
extraUsedMaterialIndices	Indices of materials that should be considered "used" even if they're not referenced by anything else in the glTF.

◆ removeUnusedMeshes()

static void CesiumGltfContent::GltfUtilities::removeUnusedMeshes	(	CesiumGltf::Model &	gltf,
		const std::vector< int32_t > &	extraUsedMeshIndices = {} )

static

Removes unused meshes from the given glTF model.

Parameters

gltf	The glTF to remove unused meshes from.
extraUsedMeshIndices	Indices of meshes that should be considered "used" even if they're not referenced by anything else in the glTF.

◆ removeUnusedSamplers()

static void CesiumGltfContent::GltfUtilities::removeUnusedSamplers	(	CesiumGltf::Model &	gltf,
		const std::vector< int32_t > &	extraUsedSamplerIndices = {} )

static

Removes unused samplers from the given glTF model.

Parameters

gltf	The glTF to remove unused samplers from.
extraUsedSamplerIndices	Indices of samplers that should be considered "used" even if they're not referenced by anything else in the glTF.

◆ removeUnusedTextures()

static void CesiumGltfContent::GltfUtilities::removeUnusedTextures	(	CesiumGltf::Model &	gltf,
		const std::vector< int32_t > &	extraUsedTextureIndices = {} )

static

Removes unused textures from the given glTF model.

Parameters

gltf	The glTF to remove unused textures from.
extraUsedTextureIndices	Indices of textures that should be considered "used" even if they're not referenced by anything else in the glTF.

◆ setNodeTransform()

static void CesiumGltfContent::GltfUtilities::setNodeTransform	(	CesiumGltf::Node &	node,
		const glm::dmat4x4 &	newTransform )

static

Sets the transformation matrix for a given node.

This sets only the local transform of the node. It does not affect the transforms of any ancestor or descendant nodes, if present.

Parameters

node	The node on which to set the transformation matrix.
newTransform	The new transformation matrix.

The documentation for this struct was generated from the following file:

/home/runner/work/cesium-native/cesium-native/CesiumGltfContent/include/CesiumGltfContent/GltfUtilities.h

Classes

Static Public Member Functions

Detailed Description

Member Function Documentation

◆ applyGltfUpAxisTransform()

◆ applyRtcCenter()

◆ collapseToSingleBuffer()

◆ compactBuffer()

◆ compactBuffers()

◆ computeBoundingRegion()

◆ getNodeTransform()

◆ intersectRayGltfModel()

◆ moveBufferContent()

◆ parseGltfCopyright() [1/2]

◆ parseGltfCopyright() [2/2]

◆ removeUnusedAccessors()

◆ removeUnusedBuffers()

◆ removeUnusedBufferViews()

◆ removeUnusedImages()

◆ removeUnusedMaterials()

◆ removeUnusedMeshes()

◆ removeUnusedSamplers()

◆ removeUnusedTextures()

◆ setNodeTransform()